In a communication system, data congestion has become more serious due to variety of contents and an increase in high capacity contents such as High Definition (HD) contents and Ultra High Definition (UHD) contents. Further, due to the data congestion, contents which a sender, for example, host A transmits is not normally transferred to a receiver, for example, host B, and some of the contents are lost on route.
In general, since data is transmitted in the unit of packets, the loss of contents is generated in the unit of packets. The packet includes a block of data to be transmitted, address information, and management information. The data block may be, for example, a payload, the address information may be a source address or a destination address, and the management information may be, for example, a header.
Accordingly, when the packet loss is generated in the network, the receiver cannot receive the lost packet, and thus cannot know a data block and management information within the lost packet. Therefore, it causes deterioration of audio quality, degradation of video image quality or an image breaking, an omission of a subtitle, a loss of a file and the like making an inconvenience for a user.
In order to prevent the packet loss, a method of artificially dropping and transmitting data that does not have a large influence on reproduction of contents from the packet to be transmitted is used as a method of reducing loads of the network. The data that does not have a large influence on the reproduction of the contents may be, for example, a B-frame. However, such a method also cannot remove the packet loss in the network, so that Application Layer-Forward Error Correction (AL-FEC) is required as a method of restoring the packet loss generated in the network even in transmission through the packet drop. Further, a method of configuring an FEC packet and transmitting/receiving the FEC packet is required.